1. Field
The present invention relates generally to telecommunications, and, more specifically, to methods and apparatus for determining geographic position of an access point of a wireless local area network (WLAN) interworked with a radio network providing communication services to user equipment devices.
2. Background
A modern communication system is expected to provide reliable data transmission for a variety of applications, including voice and data applications. In a point-to-multipoint communications context, known communication systems are based on frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and perhaps other multiple access communication schemes.
A CDMA system may be designed to support one or more CDMA standards, such as (1) the “TIA/EIA-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System” (this standard with its enhanced revisions A and B may be referred to as the “IS-95 standard”), (2) the “TIA/EIA-98-C Recommended Minimum Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Station,” also known as the “IS-98 standard,” (3) the standard sponsored by a consortium named “3rd Generation Partnership Project” (3GPP) and embodied in a set of documents including documents known as 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the “W-CDMA standard”), (4) the standard sponsored by a consortium named “3rd Generation Partnership Project 2” (3GPP2) and embodied in a set of documents including “C.S0002-A Physical Layer Standard for cdma2000 Spread Spectrum Systems,” the “C.S0005-A Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems,” (the “cdma2000 standard” collectively), (5) the 1xEV-DO standard “TIA/EIA/IS-856 cdma2000 High Rate Packet Data Air Interface Specification,” and (6) certain other standards. The standards listed above are incorporated by reference as if fully set forth herein, including annexes, appendices, and other attachments.
Many user equipment (UE) devices, for example, cellular telephones and personal digital assistants (PDAs), are configured for use with multiple wireless access technologies. For example, a cellular telephone may be capable of connecting to a CDMA Universal Mobile Telecommunications System (UMTS) network, and to a WLAN, such as a local area network compliant with one or more of the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standards. When such a user equipment device is in the service area of an access point of a WLAN, the access point may enable the user equipment device to make wireless connections through the WLAN, reducing the load on the cellular radio network that would otherwise need to carry the traffic of the user equipment device. (An access point is a device that mediates over-the-air interface of the WLAN technology and the wired backhaul or other connectivity of the WLAN to external networks.) Moreover, a connection through a WLAN may provide higher bandwidth and/or better quality of service (QoS) than would be available to the user equipment device directly from the UMTS radio network.
It is desirable and sometimes required for a provider of communication services to know the geographic location of the serviced telephones and other user equipment devices. For example, the geographic location may need to be known in order to identify the location to operators responding to an emergency (e.g., 911 in U.S. and 112 in certain European locales) call; it may also be desired to provide the user with other location-specific services and advertising.
In case of conventional land-line telephones, determining the geographic location generally does not present a problem, because each land line is associated with a physical address at which the service is provided.
In case of conventional cellular telephones connected to a radio network, determining the geographic location of a telephone also generally does not present a problem. For example, the enhanced 911 (e911) feature in the 911 emergency-calling system of North American telephone network (NATN) may activate global positioning system services, or triangulate/trilaterate from base transceiver stations of the radio network, in order to determine the telephone's geographic location, and then transmit the location through the radio network to the telephone service provider and emergency operator.
When connectivity is provided to a user equipment device through a WLAN access point, however, the above-described method may not apply. Even assuming that the user equipment device is in the immediate vicinity of the access point (because of the relatively short WLAN communication range), the location of the access point itself may not be known. Consider, for example, an access point of a WLAN that is configured to provide telephone services through voice over Internet Protocol (VoIP). The geographic location of the access point may not be initially known, or the provisioning of the access point may be done incorrectly. Even when the geographic location of the access point is known at some point in time and the access point is correctly provisioned, the access point or the entire WLAN may be subsequently moved and connected to the Internet from a different physical location. In this case, the new location of the access point may not be known to the provider of the telephone services through that access point. The new location may be in the same building as the old location, or it may be thousands of miles away. The telephone service provider may remain unaware of the new location and of the very fact that the access point has been moved. Thus, the emergency operator may not be able to dispatch emergency services, or may dispatch emergency services to the old location instead of the new one.
One solution to this problem might be to instrument WLAN access points with a global positioning system (GPS) receiver to allow the access point to determine its location. Cost of the GPS receiver, however, may make this approach not competitive, particularly in the consumer marketplace, where the WLAN access point is often a single piece of critically price-sensitive hardware.
There is therefore a need in the art for methods and apparatus for determining geographic location of WLAN access points not instrumented with GPS receivers, and determining changes in the geographic location of the WLAN access points.